Lambo Modinat Tolani, Liu Rui, Zhang Xianglong, Zhang Yonggen, Li Yang, Sun Manji
College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China.
Animals (Basel). 2024 Jun 24;14(13):1864. doi: 10.3390/ani14131864.
The objective of this work is to investigate the chemical and nutritional value of milk thistle meal (MTM) in order to improve it and to provide theoretical support for its application in dairy cattle production. MTM was assessed in comparison with seven conventional protein feed sources, namely, soybean meal (SBM), cottonseed meal (CS), canola meal (CN), palm kernel meal (PK), rice bran meal (RB), corn germ meal (CG), and sesame meal (SS). The chemical composition of these feedstuffs was assessed using wet chemical analysis, the Cornell Net Carbohydrate and Protein System was used to evaluate the carbohydrate and protein fractions, and the in situ nylon bag technique and the modified three-step in vitro method were used to assess the rumen degradation and intestinal digestibility. Additionally, Fourier transform infrared technology was used to determine the feedstuff protein spectral molecular structure and its amino acid profile was also assessed. The result showed that MTM acid detergent fiber, lignin, unavailable nitrogen, and non-degradable carbohydrate content were higher than those of the other feedstuffs. It had a 17% and 36% rumen effective degradation rate of neutral detergent fiber and dry matter, respectively, and had the lowest small intestinal rumen undegradable protein digestibility rate. It was low in leucine, histidine, arginine, and proline, but high in methionine. The total area of amide I and amide II in the protein secondary structure was similar to that of CN and CS, and the amide I and II ratio was not different from that of RB. To sum up, MTM has a poor carbohydrate composition and is high in fiber but, in comparison to most other protein feeds, has a higher crude protein rumen effective degradation rate, similar to that of SBM, and it is a good source of methionine, a limiting amino acid. Hence, its nutritional value can be further improved for application in dairy feeding through processes such as microbial or enzymatic fermentation.
本研究旨在探讨水飞蓟粕（MTM）的化学和营养价值，以便对其进行改良，并为其在奶牛生产中的应用提供理论支持。将MTM与七种传统蛋白质饲料来源进行比较评估，这七种饲料分别是豆粕（SBM）、棉籽粕（CS）、菜籽粕（CN）、棕榈仁粕（PK）、米糠粕（RB）、玉米胚芽粕（CG）和芝麻粕（SS）。采用湿化学分析法评估这些饲料的化学成分，运用康奈尔净碳水化合物和蛋白质系统评估碳水化合物和蛋白质组分，采用原位尼龙袋技术和改良的三步体外法评估瘤胃降解率和肠道消化率。此外，利用傅里叶变换红外技术测定饲料蛋白质光谱分子结构，并评估其氨基酸谱。结果表明，MTM的酸性洗涤纤维、木质素、不可利用氮和不可降解碳水化合物含量高于其他饲料。其中性洗涤纤维和干物质的瘤胃有效降解率分别为17%和36%，小肠瘤胃不可降解蛋白质消化率最低。其亮氨酸、组氨酸、精氨酸和脯氨酸含量较低，但蛋氨酸含量较高。蛋白质二级结构中酰胺I和酰胺II的总面积与CN和CS相似，酰胺I和II的比例与RB无差异。综上所述，MTM碳水化合物组成较差，纤维含量高，但与大多数其他蛋白质饲料相比，其粗蛋白瘤胃有效降解率较高，与SBM相似，且是限制性氨基酸蛋氨酸的良好来源。因此，可通过微生物或酶发酵等工艺进一步提高其营养价值，以应用于奶牛饲养。
